Module java.xml
Package javax.xml.namespace

Class QName

java.lang.Object
javax.xml.namespace.QName
All Implemented Interfaces:
Serializable
public class QName
extends Object
implements Serializable

QName represents a qualified name as defined in the XML specifications: XML Schema Part2: Datatypes specification, Namespaces in XML.

The value of a QName contains a Namespace URI, local part and prefix.

The prefix is included in QName to retain lexical information when present in an XML input source. The prefix is NOT used in QName.equals(Object) or to compute the QName.hashCode(). Equality and the hash code are defined using only the Namespace URI and local part.

If not specified, the Namespace URI is set to XMLConstants.NULL_NS_URI. If not specified, the prefix is set to XMLConstants.DEFAULT_NS_PREFIX.

QName is immutable.

Since:
1.5
See Also:
XML Schema Part2: Datatypes specification, Namespaces in XML, Serialized Form

  • Constructor Details

  • Method Details

    • getNamespaceURI

      public String getNamespaceURI()

      Get the Namespace URI of this QName.

      Returns:
      Namespace URI of this QName

    • getLocalPart

      public String getLocalPart()

      Get the local part of this QName.

      Returns:
      local part of this QName

    • getPrefix

      public String getPrefix()

      Get the prefix of this QName.

      The prefix assigned to a QName might NOT be valid in a different context. For example, a QName may be assigned a prefix in the context of parsing a document but that prefix may be invalid in the context of a different document.

      Returns:
      prefix of this QName

    • equals

      public final boolean equals​(Object objectToTest)

      Test this QName for equality with another Object.

      If the Object to be tested is not a QName or is null, then this method returns false.

      Two QNames are considered equal if and only if both the Namespace URI and local part are equal. This method uses String.equals() to check equality of the Namespace URI and local part. The prefix is NOT used to determine equality.

      This method satisfies the general contract of Object.equals(Object)

      Overrides:
      equals in class Object
      Parameters:
      objectToTest - the Object to test for equality with this QName
      Returns:
      true if the given Object is equal to this QName else false
      See Also:
      Object.hashCode(), HashMap

    • hashCode

      public final int hashCode()

      Generate the hash code for this QName.

      The hash code is calculated using both the Namespace URI and the local part of the QName. The prefix is NOT used to calculate the hash code.

      This method satisfies the general contract of Object.hashCode().

      Overrides:
      hashCode in class Object
      Returns:
      hash code for this QName Object
      See Also:
      Object.equals(java.lang.Object), System.identityHashCode(java.lang.Object)

    • toString

      public String toString()

      String representation of this QName.

      The commonly accepted way of representing a QName as a String was defined by James Clark. Although this is not a standard specification, it is in common use, e.g. Transformer.setParameter(String name, Object value). This implementation represents a QName as: "{" + Namespace URI + "}" + local part. If the Namespace URI .equals(XMLConstants.NULL_NS_URI), only the local part is returned. An appropriate use of this method is for debugging or logging for human consumption.

      Note the prefix value is NOT returned as part of the String representation.

      This method satisfies the general contract of Object.toString().

      Overrides:
      toString in class Object
      Returns:
      String representation of this QName

    • valueOf

      public static QName valueOf​(String qNameAsString)

      QName derived from parsing the formatted String.

      If the String is null or does not conform to QName.toString() formatting, an IllegalArgumentException is thrown.

      The String MUST be in the form returned by QName.toString().

      The commonly accepted way of representing a QName as a String was defined by James Clark. Although this is not a standard specification, it is in common use, e.g. Transformer.setParameter(String name, Object value). This implementation parses a String formatted as: "{" + Namespace URI + "}" + local part. If the Namespace URI .equals(XMLConstants.NULL_NS_URI), only the local part should be provided.

      The prefix value CANNOT be represented in the String and will be set to XMLConstants.DEFAULT_NS_PREFIX.

      This method does not do full validation of the resulting QName.

      The Namespace URI is not validated as a URI reference. The local part is not validated as a NCName as specified in Namespaces in XML.

      Parameters:
      qNameAsString - String representation of the QName
      Returns:
      QName corresponding to the given String
      Throws:
      IllegalArgumentException - When qNameAsString is null or malformed
      See Also:
      QName.toString()